66 Cat rear end noise question

Hi all. I am a happy new owner of a gorgeous '66 wildcat convertible and brand new member to this great group. Sorry in advance for the length post. If it is inappropriate in this group, please let me know.

I've noticed a slight noise as described below that I think is coming from the left rear end and I'm hoping some of you experienced vintage Buick owners can provide some help.

The car is a 66 Wildcat convertible (not GS) automatic with the 401 CI engine. It has 77K miles.

The diff cover is painted and there is form-a-gasket type material around edge. Not sure if this was simply due to the removal and painting of the cover or if the diff was worked on.

Noise - not really a distinct "grinding" - more of a "rubbing". Kinda like a noise from a thrust type force on some bearings (or maybe some slop in the diff gears?). The noise is not very loud. I've had rear axle bearings totally go out on an old Crown Victoria and it is definitely not the same noise as that. Those bearings rode right on the axle and did a "lathe job" on it when they went out. I'll never forget that noise!

The noise occurs when putting a bit of sideways force on the vehicle in a left turn only and only when no torque is being applied to drive train. If gas is applied and torque put to wheels, noise diminishes greatly or goes away. Note that noise seems to get louder as sideways force increases when turning vehicle. Very slight turns do not produce the noise. It seems like a sidways force pulling outward on the axle when there is little or no load on the diff gears may be causing the noise. No similar noise occurs when in a left turn.

I'm thinking about just replacing all axle and diff bearings. Actually, I'm thinking about having it done rather than doing it myself. I have the shop manual and from that and my previously noted experience replacing a real axle bearing, I don't think I have the shop facility or tools to do it right myself.

Oh, and I would be grateful for any info on a source for the bearings, seals, and collapsable collar, etc. that will be required for this job.

In reading up on this, it appears to me that the rear ends for Cats may have gone through changes sometime in the middle of '66. if anyone can enlighten me on that, I would much appreciate it. If this is true, I'd like to use mechanics' knowledge of this to determine how much experience they have working on old Buick rear ends and whether or not I want to choose them for the work. I'm very leery about having someone work on our new "baby".

Any help or advice would be greatly appreciated.

Thanks.

 

The rear diffs are pretty stout in these cars. Rear axle bearings are a possibility though. Another thing, noise travels in metal. What sounds like it may be coming from the rear could actually be front wheel bearings. I would check those 1st before pulling the axles. Pulling the rear axles is easy enough.

 

Anyone else have experience or advice?

 

Both my Rivs did that once or twice and each time it was an axle bearing.......I'd put my money on that.

If you feel ambitious and aren't afraid to, put it up on jack stands, start her up and put her in drive, and with the engine idling hold a long screwdriver against your ear and touch the other end to the area near the wheel bearings and listen. Mine made a loud distinctive noise exactly in that spot. Just be careful doing this and make sure the stands are safely placed under the axle and that you have chocks under the front wheels! :idea2:

 

Thanks Nailheadina67.

I pretty much decided that I was going to just replace all wheel bearings, front and back. We just got the cat and I figured it was just a good idea to change them as preventative maintenance. I was hoping that I wouldn't get someone telling me that they had experience with just such a noise caused by a problem in their differential.

Do you know if the axles are easy to pull on a 66 Cat? Do you simply remove a retainer plate and pull the axle or do you need to open the diff? I pulled an axle on an old Grand Marquis and it was necessary to open the diff to remove retainer clips on the axle. I needed a slap hammer (which I didn't have) to remove the bearing from the axle housing and I messed with it that for days until I found someone twith the right tool. I'm guessing that some tools will be needed that I don't have, such as a wheel puller, slap hammer, etc. Also, I saw somewhere that the bearings are pressed on this axle and it is best to take the axle to a machine shop to have the old ones pulled and the new ones pressed on. Do you know if that is true?

I may just find a garage that has experience with older GM's like this and have them do the rear bearings.

Thanks,
Ken

 

They didn't start using "C" locks until '68, so you need not open up the pumpkin. You probly will need a slide hammer though, and the backing plates can just be wired to the springs to hold them up in place while the axles are out. You definitely must have the bearings pressed on and off the axles. Many shops will do this for you. Spend the extra dough on good bearings if you can find them.....chinese bearings aren't very good.

These are actually really easy to do, sometimes they just slide right out but plan on renting a slide hammer. Once I got mine out with a chain and a sledge hammer attched to the wheel studs. uzzled: The second time I wasn't as lucky.

 

Thanks Nailheadina67. Your advice is greatly appreciated.

My plan is to use Timken bearings - I don't think they're Chinese.

So what your saying is that the axles may just pull out or may need some "encouragement", right? If the "encouragement" is necessary, what is it that causes the axle to hang up? Is it the outside bearing race hanging up inside the axle houseing?

How does the shop know how far to press the bearings on the axle? Are there shoulders on the axle that the bearings press up against?

Ken

 

It's the outside bearing race that gets stuck in the housing. Some are just a tight fit, and some just get a little rusty and get stuck.

The bearings press up all the way to the end and stop at a shoulder so to speak. There is also a ring that locks the bearing from slipping off. Usually they split it with a chisel gun to expand it so it will come apart. A new one should come with the bearing.

When I used to work for Goodyear back in the day, I pressed my own. That bearing was stuck on the axle so hard, it bent it to come apart and the bearing exploded! The axle is hardened, so it sprung back straight and was OK. This is something that definitely must be sent out to be pressed...and it's wise to put an upside down coffee can with a hole in it to go over the axle over the bearing if it needs persuasion. A piece of bearing in your body might hurt. ou:

 

Ken, most times when removing axle shafts at home & they are stuck. Put the brake drum on backwards. Screw the lug nuts on backwards a few threads. Use the drum as a slide hammer. This will usually work except for the most stubborn axles. The axle retainer bolts go through the backing plate. If you don't remove the bolts the backing plate will stay in place & you will be less likely to break the brake line. Of course if a little bending broke the brake line in the 1st. place it was time to replace them anyway.

 

That happened to me. :rant:

 

There is a old mechanics trick, to get the axel out, get a chain about 20 ft long that will go over the lug bolts. After the 4 retainer bolts are out and when you are ready to pull the axel, put the chain on one of the lug bolts and put a lug nut on backwards on top of it. Then grab the other end of the chain , face away from the car and ''pop'' the chain like a bull whip. It might take a time or two but the axel will usually pop right out.
On the axel bearings, wrap a rag around the old bearing and bust the outer race all to pieces with a 2 lb hammer. then take a cold chizel and parallel with the axel shaft score the inner bearing with a hammer. wear eye protection. score in a couple of places. Then the old race will press off a lot easier.

 

My grandfather just suggested I do the exact same thing! Although he claims he invented the whole idea... =p

I've got a similar noise, in my 64, which I believe to come from the right rear.

I've got it in the shop right now for rear axle seals/bearings, propeller shaft centerlink bearing/support bracket, and neutral safety switch.

 

1971 Buick Rear end noise opinion?

My rear end is making noise. Someone said to get graphite Gear oil?
This will help quiet the noise down? Ever hear of such?
Thanks
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I wouldn't think quieting the noise would be any good of an idea.. Think it'd be best to fix the noise..., no?

That's like placing duct-tape over a crying baby's mouth instead of giving him food??

 

I have near the exact same noise, happens at the same times as you but it was from my left front. Finally pulled the left front wheel off and found the backing plate is no more.
But there was still a hunk around the hub that I guess just spun its guts out but when turning it rubbed. And just like yours on when it makes noise or doesnt.

Was an easy fix though.

 

:TU: Good posts guys! Length of chain or brake drum slide hammers! I like the ideas! Git-R-Dun, right?

I learn something new every time I log on. Again, great tips! Thanks!

 

Rear wheel bearing is where i would start also. The car is old probably been sitting here and there for years and depending on the bearing type tapered being diff oil supplied or seal bearing...The bearing could have just dried up . Tapered bearing will crush the outer seal enouh that there will be a bit more end play then wanted and ride out of the race ever so on to a differet surface area worn to on worn and make that noise. So many places to go ...Just start with the simpe things you can actual lookat and evaulate.

Keep us posted. Thanks, Jim

I know pittsburgh is not super right next door but if I can help let me know.

Parts I can definetely help with. If you brought the whole rear I can rebuild it...stuff like that. I do make trips to Youngstown yard quite often and could catch you about 1/2 way too. Jim

 

I'm thinking my noise was a combination of things.

I just had the rear axle seals and wheel bearings done, the centerlink driveshaft support and bearing, and the driveshaft<-->trans seal replaced.. Oh and the rear shocks done too.

My noise has gone away completely. Thank god. What a scary noise that was. It sounded like the axleshaft was broken. Now it's as quiet as my '99 Subaru.

 

Wheel bearings can make a lot of noise.....glad you found it and it wasnt as expensive as you thought it would be.